Detonating cord interrupt device and method for transporting an explosive device

ABSTRACT

A detonating cord interrupt device ( 140 ) is positionable between two segments of detonating cord ( 126, 134 ). The detonating cord interrupt device ( 140 ) includes a housing ( 130 ), a first booster ( 128 ) at least partially disposed within the housing ( 130 ) and a second booster ( 132 ) at least partially disposed within the housing ( 130 ) and having a spaced apart relationship with the first booster ( 128 ). A detonation transfer interrupt member ( 138 ) is removably positionable within the housing ( 130 ) in the space between the first and second boosters ( 128, 132 ) such that the transfer of a detonation from one of the first and the second boosters ( 128, 132 ) to the other of the first and the second boosters ( 128, 132 ) is prevented when the detonation transfer interrupt member ( 138 ) is positioned within the housing ( 130 ).

TECHNICAL FIELD OF THE INVENTION

[0001] This invention relates, in general, to perforating a cased wellbore that traverses a subterranean hydrocarbon bearing formation and, in particular, to a detonating cord interrupt device for preventing the premature detonation of the shaped charges within a perforating gun assembly during transportation.

BACKGROUND OF THE INVENTION

[0002] Without limiting the scope of the present invention, its background will be described with reference to perforating a subterranean formation with a perforating gun assembly, as an example.

[0003] After drilling a section of a subterranean wellbore that traverses a formation, individual lengths of relatively large diameter metal tubulars are typically secured together to form a casing string that is positioned within the wellbore. This casing string increases the integrity of the wellbore and provides a path for producing fluids from the producing intervals to the surface. Conventionally, the casing string is cemented within the wellbore. To produce fluids into the casing string, hydraulic openings or perforations must be made through the casing string, the cement and a short distance into the formation.

[0004] Typically, these perforations are created by detonating a series of shaped charges that are disposed within the casing string and are positioned adjacent to the formation. Specifically, one or more charge carriers are loaded with shaped charges that are connected with a detonator via a detonating cord. The charge carriers are then connected within a tool string that is lowered into the cased wellbore at the end of a tubing string, wireline, slick line, coil tubing or other conveyance. Once the charge carriers are properly positioned in the wellbore such that the shaped charges are adjacent to the formation to be perforated, the shaped charges may be fired. If more than one downhole zone is to be perforated, a select fire perforating gun assembly may be used such that once the first zone is perforated, subsequent zones may be perforated by repositioning and firing the previously unfired shaped charges without tripping out of the well.

[0005] The shaped charges used to perforate the casing include high explosives and must therefore be handled with extreme caution. For example, it is imperative that the high explosives are not prematurely initiated causing the shaped charge to detonate. Accordingly, in the interest of safety and due to governmental regulations relating to the transportation of explosive devices, perforating gun assemblies are typically not armed, i.e., the detonators are not installed, until the perforating gun assembly arrives at the rig site.

[0006] It has been found, however, that installing detonators in the perforating gun assembly at the rig site has several drawbacks. For example, the person installing the detonators is commonly under a time constraint to complete to the installation as rig time is very expensive. In addition, the rig environment, such as weather conditions, work area, lighting and the like, may not be as conducive as the manufacturer's shop environment for the intricate assembly required during the installation of the detonators. Furthermore, the level of skill of the person installing the detonators at the rig site may not be as great as that of a technician in the manufacturer's shop. These inherent limitations of the rig environment have lead to mistakes being made in the installation of detonators into perforating gun assemblies resulting in the failure of certain perforating gun assemblies to fire.

[0007] Therefore a need has arisen for an apparatus and method that provide for the safe transportation of an armed perforating gun assembly such that the intricate work of installing the detonators may be performed in the manufacturer's shop as opposed to the rig site. A need has also arisen for such an apparatus and method that prevent the premature detonation of the shaped charges in the armed perforating gun assembly. Further, a need has arisen for such an apparatus and method that minimize the required on site preparation of the armed perforating gun assembly.

SUMMARY OF THE INVENTION

[0008] The present invention disclosed herein comprises a perforating gun assembly that provides for the safe transportation of an armed perforating gun assembly such that the intricate work of installing the detonators may be performed in the manufacturer's shop as opposed to the rig site. To achieve this result, the perforating gun assembly of the present invention uses a detonating cord interrupt device that prevents the premature detonation of the shaped charges in the armed perforating gun assembly. In addition, the detonating cord interrupt device requires minimal on site manipulation to allow a planned detonation of the shaped charges.

[0009] The detonating cord interrupt device of the present invention comprises a housing, a first booster at least partially disposed within the housing, a second booster at least partially disposed within the housing and having a spaced apart relationship with the first booster and a detonation transfer interrupt member removably positionable within the housing in the space between the first and second boosters.

[0010] In one embodiment, the detonation transfer interrupt member extends transversely through an opening in the housing. In this embodiment, the detonation transfer interrupt member may be a substantially cylindrical member that is inserted through a round opening in the housing. The detonation transfer interrupt member may be constructed from a variety of materials such as metals, polymers, elastomers and combination thereof.

[0011] In operation, the detonating cord interrupt device prevents the transfer of a detonation from one of the boosters to the other booster when the detonation transfer interrupt member is positioned within the housing. Likewise, the detonating cord interrupt device allows the transfer of a detonation from one of the boosters to the other booster when the detonation transfer interrupt member is not positioned within the housing.

[0012] The detonating cord interrupt device may be positioned within a detonating cord to prevent the premature propagation of a detonation wave through the detonating cord. For example, the detonating cord interrupt device may be positioned between a first and a second segment of a detonating cord. In this configuration, the first booster is operably associated with the first segment of detonating cord and the second booster operably associated with the second segment of detonating cord. More specifically, the first booster may be securably coupled to the first segment of detonating cord by crimping and the second booster may be securably coupled to the second segment of detonating cord by crimping. Likewise, the first and second boosters may be securably coupled to the housing by crimping.

[0013] Such an arrangement, may be used within a perforating gun assembly such that the perforating gun assembly may be armed prior to transportation. The perforating gun assembly of the present invention comprises a plurality of shaped charges positioned within a charge carrier and a detonating cord having first and second segments. The second segment of the detonating cord is operably coupled to the shaped charges. A detonator is operably coupled to the first segment of the detonating cord and is operable to initiate a detonation within the first segment of the detonating cord. The detonating cord interrupt device is positioned between the first and second segments of the detonating cord to prevent a detonation of the shaped charges in the event of a premature initiation of the detonator.

[0014] The charge carrier of the perforating gun assembly may be a ported carrier having ports substantially radially aligned with the shaped charges and a port axially aligned with the detonating cord interrupt device. Port plugs are secured within the ports to provide a fluid seal and prevent any fluids from entering the perforating gun assembly prior to firing.

[0015] In another aspect, the present invention comprises a method for preventing the detonation of shaped charges in an armed perforating gun assembly. The method includes positioning a plurality of shaped charges within a charge carrier, operably coupling a detonating cord to the shaped charges, operably coupling a detonator to the detonating cord and positioning a detonating cord interrupt device within the detonating cord between the detonator and the shaped charges.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:

[0017]FIG. 1 is schematic illustration of an offshore oil and gas platform operating a perforating gun assembly of the present invention;

[0018]FIG. 2 is a side view partially cut away of a perforating gun assembly of the present invention positioned within a wellbore;

[0019]FIG. 3 is a side view of a detonator, two segments of detonating cord and a detonating cord interrupt device of the present invention;

[0020]FIG. 4 is a cross sectional view of detonating cord interrupt device of the present invention positioned between two segments of detonating cord prior to a premature detonation;

[0021]FIG. 5 is a cross sectional view of detonating cord interrupt device of the present invention positioned between two segments of detonating cord following a premature detonation;

[0022]FIG. 6 is a cross sectional view of detonating cord interrupt device of the present invention positioned between two segments of detonating cord prior to a planned detonation;

[0023]FIG. 7 is a cross sectional view of detonating cord interrupt device of the present invention positioned between two segments of detonating cord following a planned detonation; and

[0024]FIG. 8 is a cross sectional view of an alternate embodiment of a detonating cord interrupt device of the present invention positioned between two segments of detonating cord.

DETAILED DESCRIPTION OF THE INVENTION

[0025] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the present invention.

[0026] Referring initially to FIG. 1, a perforating gun assembly adapted for use in a wellbore operating from an offshore oil and gas platform is schematically illustrated and generally designated 10. A semi-submersible platform 12 is centered over a submerged oil and gas formation 14 located below sea floor 16. A subsea conduit 18 extends from deck 20 of platform 12 to wellhead installation 22 including blowout preventers 24. Platform 12 has a hoisting apparatus 26 and a derrick 28 for raising and lowering pipe strings.

[0027] A wellbore 36 extends through the various earth strata including formation 14. Casing 38 is cemented within wellbore 36 by cement 40. When it is desired to perforate casing 38 adjacent to formation 14, a perforating gun assembly 42 is lowered into casing 38 via conveyance 44 such as a wireline, electric line or coiled tubing. Thereafter, an electric signal is sent to a detonator 46 which initiates the detonation of the shaped charges that are disposed within perforating gun assembly 42. Upon detonation, perforations are created that extend outwardly through casing 38, cement 40 and into formation 14.

[0028] Even though FIG. 1 depicts a vertical well, it should be noted by one skilled in the art that the perforating gun assembly of the present invention is equally well-suited for use in wells having other geometries such as deviated wells, inclined wells or horizontal wells. Also, even though FIG. 1 depicts an offshore operation, it should be noted by one skilled in the art that the perforating gun assembly of the present invention is equally well-suited for use in onshore operations.

[0029] Referring now to FIG. 2, therein is depicted a perforating gun assembly 60 positioned in a wellbore 62 that penetrates formation 64. A casing 66 lines wellbore 62 and is secured in position by cement 68. A conveyance 70 is coupled to perforating gun assembly 60 at a cable head 72. A collar locator 74 is positioned below cable head 72 to aid in the positioning of perforating gun assembly 60 in wellbore 62.

[0030] A fluid such as drilling fluid (not shown) fills the annular region between perforating gun assembly 60 and casing 66. In the illustrated embodiment, perforating gun assembly 60 has a ported carrier 80 having port plugs 82 positioned therein that create a fluid seal and prevent any wellbore fluids from entering perforating gun assembly 60. Radially aligned with port plugs 82 is a respective one of a plurality of shaped charges, such as shaped charge 86. Each of the shaped charges includes an outer housing, such as housing 88 of shaped charge 86, and a liner, such as liner 90 of shaped charge 86. Disposed between each housing and liner is a quantity of high explosive.

[0031] In the illustrated embodiment, the shaped charges are retained within carrier 80 by a support member 92 which includes an outer charge holder sleeve 94 and an inner charge holder sleeve 96. In this configuration, outer charge holder sleeve 94 supports the discharge ends of the shaped charges, while inner charge holder sleeve 96 supports the initiation ends of the shaped charges. Disposed within inner tube 96 is a detonating cord 98, such as a primacord, which is operable to detonate the shaped charges. In the illustrated embodiment, the initiation ends of the shaped charges extend across the cental longitudinal axis of perforating gun assembly 60 allowing detonating cord 98 to connect to the high explosive within the shaped charges through an aperture defined at the apex of the housings of the shaped charges.

[0032] Each of the shaped charges is longitudinally and radially aligned with a port plug 82 in carrier 80 when perforating gun assembly 60 is fully assembled. In the illustrated embodiment, the shaped charges are arranged in a spiral pattern such that each shaped charge is disposed on its own level or height and is to be individually detonated so that only one shaped charge is fired at a time. It should be noted, however, by those skilled in the art that alternate arrangements of shaped charges may be used, including cluster type designs wherein more than one shaped charge is at the same level and is detonated at the same time, without departing from the principles of the present invention.

[0033] Perforating gun assembly 60 also includes a detonator subassembly 100. Detonator subassembly 100 has a ported housing 102 that receives a port plug 104. Disposed within detonator subassembly 100 is a detonator 106 that is coupled to an electrical energy source via electrical wire 108. Detonator 106 may be any type of detonator that is suitable for initiating a detonation in a detonating cord as the present invention is detonator independent, such detonators being of the type that are well known in the art or subsequently discovered. Detonator 106 is coupled to a segment of detonating cord 110. Positioned between detonating cord 110 and detonating cord 98, which extends into detonator subassembly 100 from carrier 80, is a detonating cord interrupt device 112.

[0034] Detonating cord interrupt device 112 is used to selectively prevent and allow the propagation of a detonation from detonating cord 110 to detonating cord 98. More specifically, when perforating gun assembly 60 is assembled in the shop, detonator 106 is installed within perforating gun assembly 60 along with the shaped charges. Importantly, for safety during transportation of the armed perforating gun assembly 60 from the shop to the rig site, detonating cord interrupt device 112 is positioned in its detonation interpret configuration within the explosive train between detonator 106 and the shaped charges. Accordingly, even if detonator 106 were to prematurely initiate a detonation, detonating cord interrupt device 112 would prevent the detonation wave from transferring from detonating cord 110 to detonating cord 98.

[0035] Once the armed perforating gun assembly 60 has been safely transported to the rig site, port plug 104 is removed such that a technician can reconfigure detonating cord interrupt device 112 from its detonation interpret configuration to its non detonation interrupt configuration. Thereafter, perforating gun assembly 60 may be attached to a conveyance and run downhole to the desired location. To detonate the shaped charges, an electrical signal is sent to detonator 106 via electrical wire 108 that initiates a detonation within detonating cord 110. The detonation transfers from detonating cord 110 to detonating cord 98, as explained in greater detail below, by passing through detonating cord interrupt device 112 in its non detonation interrupt configuration. The detonation wave then progresses through detonating cord 98 to initiate the detonation of the shaped charges, thereby perforating the well.

[0036] Even though a single perforating gun assembly is depicted in FIG. 2, it should be appreciated by those skilled in the art that any number of perforating gun assemblies may be included in the tool string and are considered within the scope of the present invention as the number of perforating gun assemblies will be dependent upon the length of the interval or intervals being perforated as well as the number of intervals being perforated in a single trip using, for example, select fire perforating gun assemblies which will require multiple detonating cord interrupt devices. Also, even though perforating gun assembly 60 is depicted in a bottom up firing configuration, it should be understood by those skilled in the art that the present invention in equally well-suited for use in perforating gun assemblies having a top down firing configuration.

[0037] Referring next to FIG. 3, therein is presented an enlarged view of a first portion of an explosive train according to the present invention that is generally designated 120. Explosive train 120 includes detonator 122 that is coupled to an electrical input line 124 and to a segment of detonating cord 126. On the opposite end of detonating cord 126 is a booster 128 that is securably coupled to detonating cord 126 by crimping. The opposite end of booster 128 (not visible in FIG. 3) extends into housing 130 and is secured therein by crimping housing 130. Housing 130 may be constructed from a variety of materials including metals such as steels and aluminum, polymers or other suitably durable material. A booster 132 extends into the opposite end of housing 130 and is similarly secured therein by crimping housing 130. Extending from the opposite end of booster 132 is a segment of detonating cord 134. Housing 130 has an opening 136 through which a detonation transfer interrupt member 138 transversely extends. Detonation transfer interrupt member 138 may be constructed from any suitable material such as metals including steels, copper, aluminum and the like, polymers, elastomers or combination thereof and the like. Together, housing 130, boosters 128, 132 and detonation transfer interrupt member 138 form detonating cord interrupt device 140. Even though the coupling of the detonating cords to the boosters and the boosters to the housing has been depicted as crimping, it should be noted by those skilled in the art that other techniques could alternatively be used for such coupling, including, but not limited to, use of adhesives, a friction fit or combinations thereof and the like.

[0038] As best seen in FIG. 4, detonating cord interrupt device 140 is in its detonation interrupt configuration prior to the detonation of either detonating cord 126 or detonating cord 134. In the illustrated embodiment, detonating cord 126 includes explosive 142, booster 128 includes explosive 144, detonating cord 134 includes explosive 146 and booster 132 includes explosive 148. As stated above, if one of the detonating cords were to be detonated when detonating cord interrupt device 140 is in its detonation interrupt configuration wherein detonation transfer interrupt member 138 is positioned with opening 136, the detonation would not transfer to the opposing detonating cord.

[0039] Specifically and as depicted in FIG. 5 in an idealized manner, following the detonation of detonating cord 126 and booster 128, the detonation does not transfer to booster 132, detonating cord 134 or any other explosive device in the downstream explosive train as detonation transfer interrupt member 138 is positioned within opening 136 of housing 130. As such, detonating cord interrupt device 140 prevents the propagation of the detonation thereacross.

[0040] Once the perforating gun assembly including detonating cord interrupt device 140 is ready to be fired, detonation transfer interrupt member 138 is removed from opening 136 in housing 130, as best seen in FIG. 6. Thereafter and as depicted in FIG. 7 in an idealized manner, following the detonation of detonating cord 126 and booster 128, the detonation transfers to the facing booster 132, detonating cord 134 and any other explosive device in the downstream explosive train as detonation transfer interrupt member 138 is not positioned within opening 136 of housing 130. As such, in this configuration, detonating cord interrupt device 140 allows the propagation of the detonation thereacross.

[0041] Even though FIGS. 4-7 have depicted a gap between the ends of boosters 128, 132 and detonating cord interrupt device 140, it should be understood by those skilled in the art that the optimal distance between the facing boosters will depend on a variety of factors such as the type of booster used, the diameter of housing 130 and the like. For example, it may be desirable in some cases to have the ends of the facing boosters contact the detonation transfer interrupt member when the detonation transfer interrupt member is positioned with the housing.

[0042] Specifically, as depicted in FIG. 8, detonating cord interrupt device 240 includes a booster 228 that is connected to a segment of detonating cord 226. Likewise, booster 232 is connected to a segment of detonating cord 234. Boosters 228, 232 each extend into housing 230 such that their respective ends contact detonation transfer interrupt member 238 if detonation transfer interrupt member 238 is positioned with opening 236 of housing 230. As illustrated, detonating cord 226 includes explosive 242, booster 228 includes explosive 244, detonating cord 234 includes explosive 246 and booster 232 includes explosive 248. Detonating cord interrupt device 240 selectively prevents and allows the transfer of a detonation thereacross as described above with reference to detonating cord interrupt device 140.

[0043] Even though FIGS. 3-8 have depicted the detonation transfer interrupt member as being cylindrical and the opening in the housing of the detonating cord interrupt device as being round, it should be clearly understood by those skilled in the art that detonation transfer interrupt members having alternate shapes being positionable in correspondingly configured openings in the housing of the detonating cord interrupt devices is contemplated and considered within the scope of the present invention. Such other shapes including, but not limited to, detonation transfer interrupt members having square cross sections, rectangular cross sections, or other polygon shaped cross sections, oval cross sections or other symmetric or non symmetric cross sections.

[0044] While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments. 

1. A perforating gun assembly comprising: a plurality of shaped charges positioned within a charge carrier; a detonating cord operably coupled to the shaped charges; a detonator operable to initiate a detonation within the detonating cord; and a detonating cord interrupt device positioned within the detonating cord between the detonator and the shaped charges.
 2. The perforating gun assembly as recited in claim 1 wherein the charge carrier is a ported carrier having ports substantially radially aligned with the shaped charges and a port axially aligned with the detonating cord interrupt device, the ports having port plugs positioned therein prior to firing the perforating gun assembly that provide a fluid seal with the ports.
 3. The perforating gun assembly as recited in claim 1 wherein the detonating cord has a first segment and a second segment and wherein the detonating cord interrupt device is positioned between the first and second segments.
 4. The perforating gun assembly as recited in claim 3 wherein the detonating cord interrupt device further comprises a first booster operably associated with the first segment of the detonating cord and a second booster operably associated with the second segment of the detonating cord, the first and second boosters at least partially disposed within a housing and having a spaced apart relationship with one another.
 5. The perforating gun assembly as recited in claim 4 wherein the first booster is securably coupled to the first ,segment of the detonating cord by crimping, the second booster is securably coupled to the second segment of the detonating cord by crimping and the first and second boosters are securably coupled to the housing by crimping.
 6. The perforating gun assembly as recited in claim 4 wherein the detonating cord interrupt device further comprises a detonation transfer interrupt member removably positionable within the housing in the space between the first and second boosters.
 7. The perforating gun assembly as recited in claim 6 wherein the transfer of a detonation from one of the first and the second boosters to the other of the first and the second boosters is prevented when the detonation transfer interrupt member is positioned within the housing.
 8. The perforating gun assembly as recited in claim 6 wherein the transfer of a detonation from one of the first and the second boosters to the other of the first and the second boosters is allowed when the detonation transfer interrupt member is not positioned within the housing.
 9. The perforating gun assembly as recited in claim 6 wherein the detonation transfer interrupt member extends transversely through an opening in the housing.
 10. The perforating gun assembly as recited in claim 6 wherein the detonation transfer interrupt member further comprises a substantially cylindrical member. 11-26. (Cancelled)
 27. A perforating gun assembly comprising: a plurality of shaped charges positioned within a charge carrier; a detonating cord having first and second segments, the second segment of the detonating cord operably coupled to the shaped charges; a detonator operable to initiate a detonation within the first segment of the detonating cord; and a detonating cord interrupt device positioned between the first and second segments of the detonating cord, the detonating cord interrupt device having a housing, a first booster operably associated with the first segment of the detonating cord, a second booster operably associated with the second segment of the detonating cord, the first and second boosters at least partially disposed within the housing and having a spaced apart relationship with one another and a detonation transfer interrupt member removably positionable within the housing in the space between the first and second boosters, such that the transfer of a detonation from the first booster to the second booster is prevented when the detonation transfer interrupt member is positioned within the housing and the transfer of a detonation from the first booster to the second booster is allowed when the detonation transfer interrupt member is not positioned within the housing.
 28. The perforating gun assembly as recited in claim 27 wherein the charge carrier is a ported carrier having ports substantially radially aligned with the shaped charges and a port axially aligned with the detonating cord interrupt device, the ports having port plugs positioned therein prior to firing the perforating gun assembly that provide a fluid seal with the ports.
 29. The perforating gun assembly as recited in claim 27 wherein the first booster is securably coupled to the first segment of the detonating cord by crimping, the second booster is securably coupled to the second segment of the detonating cord by crimping and the first and second boosters are securably coupled to the housing by crimping.
 30. The perforating gun assembly as recited in claim 27 wherein the detonation transfer interrupt member extends transversely through an opening in the housing.
 31. The perforating gun assembly as recited in claim 27 wherein the detonation transfer interrupt member further comprises a substantially cylindrical member. 32-41. (Cancelled)
 42. A perforating gun assembly comprising: a plurality of shaped charges positioned within a charge carrier; a detonating cord operably coupled to the shaped charges; a detonator operable to initiate the detonating cord; and a detonating cord interrupt device positioned within the detonating cord between the detonator and the shaped charges, the detonating cord interrupt device having a detonation transfer interrupt member that is removably positionable therein to selectively prevent and allow a detonation to be transferred thereacross.
 43. The perforating gun assembly as recited in claim 42 wherein the charge carrier is a ported carrier having ports substantially radially aligned with the shaped charges and a port axially aligned with the detonating cord interrupt device, the ports having port plugs positioned therein prior to firing the perforating gun assembly that provide a fluid seal with the ports.
 44. The perforating gun assembly as recited in claim 42 wherein the detonating cord has a first segment and a second segment and wherein the detonating cord interrupt device is positioned between the first and second segments.
 45. The perforating gun assembly as recited in claim 44 wherein the detonating cord interrupt device further comprises a first booster operably associated with the first segment of the detonating cord and a second booster operably associated with the second segment of the detonating cord, the first and second boosters at least partially disposed within a housing and having a spaced apart relationship with one another.
 46. The perforating gun assembly as recited in claim 45 wherein the first booster is securably coupled to the first segment of the detonating cord by crimping, the second booster is securably coupled to the second segment of the detonating cord by crimping and the first and second boosters are securably coupled to the housing by crimping.
 47. The perforating gun assembly as recited in claim 45 wherein the detonation transfer interrupt member is removably positionable within the housing in the space between the first and second boosters.
 48. The perforating gun assembly as recited in claim 47 wherein the transfer of a detonation from one of the first and the second boosters to the other of the first and the second boosters is prevented when the detonation transfer interrupt member is positioned within the housing.
 49. The perforating gun assembly as recited in claim 47 wherein the transfer of a detonation from one of the first and the second boosters to the other of the first and the second boosters is allowed when the detonation transfer interrupt member is not positioned within the housing.
 50. The perforating gun assembly as recited in claim 47 wherein the detonation transfer interrupt member extends transversely through an opening in the housing.
 51. The perforating gun assembly as recited in claim 47 wherein the detonation transfer interrupt member further comprises a substantially cylindrical member.
 52. A perforating gun assembly having a plurality of shaped charges positioned within a charge carrier, a detonating cord operably coupled to the shaped charges and a detonator operable to initiate the detonating cord, the perforating gun assembly comprising: a detonating cord interrupt device positioned within the detonating cord between the detonator and the shaped charges, the detonating cord interrupt device having a detonation transfer interrupt member that is removably positionable therein to selectively prevent and allow a detonation to be transferred thereacross.
 53. The perforating gun assembly as recited in claim 52 wherein the charge carrier is a ported carrier having ports substantially radially aligned with the shaped charges and a port axially aligned with the detonating cord interrupt device, the ports having port plugs positioned therein prior to firing the perforating gun assembly that provide a fluid seal with the ports.
 54. The perforating gun assembly as recited in claim 52 wherein the detonating cord has a first segment and a second segment and wherein the detonating cord interrupt device is positioned between the first and second segments.
 55. The perforating gun assembly as recited in claim 54 wherein the detonating cord interrupt device further comprises a first booster operably associated with the first segment of the detonating cord and a second booster operably associated with the second segment of the detonating cord, the first and second boosters at least partially disposed within a housing and having a spaced apart relationship with one another.
 56. The perforating gun assembly as recited in claim 55 wherein the first booster is securably coupled to the first segment of the detonating cord by crimping, the second booster is securably coupled to the second segment of the detonating cord by crimping and the first and second boosters are securably coupled to the housing by crimping.
 57. The perforating gun assembly as recited in claim 55 wherein the detonation transfer interrupt member is removably positionable within the housing in the space between the first and second boosters.
 58. The perforating gun assembly as recited in claim 57 wherein the transfer of a detonation from one of the first and the second boosters to the other of the first and the second boosters is prevented when the detonation transfer interrupt member is positioned within the housing.
 59. The perforating gun assembly as recited in claim 57 wherein the transfer of a detonation from one of the first and the second boosters to the other of the first and the second boosters is allowed when the detonation transfer interrupt member is not positioned within the housing.
 60. The perforating gun assembly as recited in claim 57 wherein the detonation transfer interrupt member extends transversely through an opening in the housing.
 61. The perforating gun assembly as recited in claim 57 wherein the detonation transfer interrupt member further comprises a substantially cylindrical member. 